Macroturbulent velocity (v_macro) for three helium lines in ζ Oph, with the x-axis normalised to the time stamp of the first spectrum (i.e. MJD = 60468.983771). Top panel: time series of all 1706 spectra with 30 s exposure times (in grey). A peak-to-peak variability in v_macro of up to 88 km s⁻¹ is seen. Dashed blue lines are the mean of the v_macro values for each night, which are consistent within their uncertainties as indicated by the shaded region. Bottom panel: v_macro time series for stacked spectra emulating 1 h (black), 30 min (blue), and 15 min (red) integration times. The peak-to-peak variability is diminished for longer integration times, but the mean v_macro is higher for longer integration times, with the nightly mean values denoted as solid lines.